The present invention relates to improved resin coated substrates. More particularly, this invention relates to an improved coated plates which employ novel resin compositions which are cleansable in aqueous solutions.
Still more particularly, the invention relates to aluminum substrates, the surface of which is coated with a composition containing a salt having the structure A-N.sub.2.sup.+ X.sup.- wherein A is an aromatic or heterocyclic residue and X is an anion of an acid; and a binder composition comprising both an acrylic polymer and an acid containing acrylic copolymer.
Most photographic elements comprise a metal sheet substrate which is coated with diazonium compound in admixture with suitable binding resins, colorants, stabilizers, exposure indicators, surfactants, and the like.
While the art discloses a plethora of photosensitive compositions useful for lithographic purposes, their serviceability is limited by the need to develop them with solutions containing substantial amounts of organic solvents. This is undesirable since these solvents are costly and their effluent is environmentally harmful.
The present invention seeks to reduce or eliminate the need for such solvents in lithographic systems by providing a photographic element with a light sensitive coating using a particular class of binding resins such that the exposed element is developable with a substantially aqueous based developer composition. Simultaneously the element shows no substantial attack to its image areas and the removed non-image area resins are substantially not re-deposited or re-adhered back onto the element after removal and the image quality and length of run of a lithographic printing plate produced from the photosensitive composition is commercially acceptable.